It said weak growth would lead to lower-than-expected tax receipts, increasing borrowing by £25bn by 2019-20.

Asked about this by BBC deputy political editor John Pienaar, Mrs May said the government was "determined to continue to live within our means", adding: "What matters is us taking the opportunities that are now open to us to develop trade around the world."

During her visit, Mrs May has faced questions about her twin goals of expanding the UK's global trade relationships after it leaves the EU while curbing migration, which the government wants to get below 100,000.

On Monday she said an expansion of the Indian visa rules would be considered if Indians who overstayed their visas in the UK could be returned more swiftly and in greater numbers.

Asked whether she was worried her crackdown on immigration could trigger a slowdown in trade negotiations, she said Indian businesses had told her they were keen to do business in the UK and that the Indian government wanted to "remove the barriers to trade and investment".